Electric-wave detector.



T. J. MURPHY. ELECTRIC WAVE DETECTOR.

APPLICATION FILED DEO.17. 1904.

mum-In :rI

Mines 65. v [777677f07f PATENTED FEB. 6, 1906.

UNITED STATES PATENT OFFICE.

THOMAS J. MURPHY, OF NEW YORK, N. Y.

ELECTRIC-WAVE DETECTOR.

Specification of Letters Patent.

Patented Feb. 6, 1906.

Application filed December 17, 1904. Serial No. 237,206.

To (ZZZ whom it may concern.-

Be it known that I, THOMAS J. MURPHY, a

sub'ect of the King of Great Britain, residing in t e city of New York, county of New York, and State of New York, have invented a new and useful Electric-Wave Detector, of which the following is a specification. invention consists, broadly, in magnetizabfe electrodes suitably arranged in respect to one another and bridged by magneticallysuspended conducting particles. For restoring the detector to its normal condition of high resistance means is provided for a movement relatively between the electrode forming part of the detector in question, (although in some cases the latter is not necessary, as the'vibration of the air and surrounding objects'due to noises, &c., is found to be sufiicient.) For the purposes of my invention an adjustable magnet is arranged in proximity to the device. A telephone-receiver or sensitive relay, or both, with battery and potentiometer is connected to the detector in the usual way. I attain these objects by the mechanism illustrated in the accompanying drawing, in which the figure is a side eleva tion and sectional view in part of detector.

Similar letters refer to similar parts throughout the drawing.

In the figure the spring-motor A, spring clips B, and contact-brush C, together with non-magnetic metal column D, are securely fastened to insulating-base E. The clips B support the detector proper, which consists of an ebonite tube F and threaded at both ends, into which metal plugs G H are screwed. A thin glass tube is fitted into ebonite sleeve F. Both plugs in question are drilled longitudinally for the reception of stems of electrodes I J. Electrode I is adjustable by means of knurled head K and j am-nut L. To insure a reliable contact, stem J is fitted with a wheel M, upon which brush N bears. O is an insulating-coupling between motor and detector. Column D supports magnet P, rendered adjustable by clamping device Q. Leads R connect battery S and telephone-receiver T in series with detector. In practice a resistance U may be used to advantage as a current-regulator.

The operation of the detector is as follows: Assuming that one at least of the electrodes is in motion, it is found that the filings, which are preferably of magnetic metal, forms a conducting-bridge across the electrodes under the influence of electric waves, and which is immediately rendered non-conducting automatically by the'movements between the conducting particles, thereby effecting the telephone receiver orrelay, as the case may be.

I do not wish to limit myself to the means as shown in the accompanying drawing of decohering my detect0ras, for example, where the incoming waves are not powerful no apparent motion is necessary at all between the electrodes or particles, and if it -does exist must be microphonic. Decohesion or state of high resistance is also arrived at by the approach of a magnet or magnetism of opposite 1polarity to existing residual magnetism in e ectrodes; nor do I confine myself to the construction or disposition shown in drawing, as the detector may be operated most eflicientlyin avertical position.

The sensitiveness and practicability of my invention as a current detector will be of great utility in the arts. I therefore do not wish to limit its uses to wireless-telegraph work alone.

The detector herein described may be used also in the arts as an instrument for the detection and measurement of minute currents of electric ty. I therefore do not confine or wish to limit its uses to wireless-telegraph work.

What I claim as my invention, and desire to secure by Letters Patent, is

1. In an electric-wave detector, electrodes in a magnetic field and bridged by ma netizable conducting particles, with means ofproducin motion between the said electrodes.

2. In an electric-wave detector, the combinati on of magnetizable electrodes in a magnetic field and brid ed by magnetic conducting particles, toget er with means of restoring the detector to its normal condition of high resistance, by a movement of the electrodes relative to one another as set forth.

In testimony whereof I have signed my name in the presence of two subscribing witnesses.

THOMAS J. MURPHY. Witnesses:

E. MURPHY, M. MURPHY. 

